How do I sign out of the Google+ Leaderboards / Achievements? (TTm Google Play version only)

You can sign out by launching the game while signed out of Google Play Games Service. The easiest way to do this might be to go into your Settings app and temporarily remove your Google account from your device, then fully exit Triple Town if it's running, then launch Triple Town. After doing so, make sure that you don't click the G+ icon or you'll be signed back in.